Nitrophenylenediamine dyes have been in existence since about 1900 and, since then, a great many nitrophenylenediamine dyes have been developed for hair dye compositions, as disclosed in U.S. Pat. Nos. 3,168,442; 4,337,061; 4,419,101 and 4,470,826.
As disclosed in the above-cited United States patents, the nitrophenylenediamine dyes are included in dyeing compositions including one or more anionic, cationic, non-ionic or amphoteric surface-active agents. Further, combinations of anionic and amphoteric detergents are commonly used for non-dye-shampoos as disclosed in the Su et al U.S. Pat. No. 4,329,334 disclosing a combination of an anionic sulfate with a cocoamidopropylsulfobetaine.
The experimental work in the nitrophenylenediamine dye area appears to have been concentrated, for the most part, in the synthesis of new nitrophenylenediamine dye compounds, as evidenced by the above cited U.S. patents. In this regard, there has been much work in Great Britain in the field of synthesis of nitrophenylenediamine dyes for hair dyeing compositions by Unilever, L'Oreal and Clairol as evidenced by the great number of British patents cited in The Chemistry of Synthetic Dyes, Volume 5, copyright 1971 by John S. Corbett, Chapter VII, pages 475-531.
It is well known that common hair shampoos contain an effective and low-to-non-irritating amount of an anionic alkyl sulfate as a principal cleansing agent, plus a number of other formulation ingredients included for product stability and customer acceptance. Likewise, direct dyeing of hair with nonionic dyes is well-known. These dyes, when used alone, work by penetrating the hair shaft without the use of peroxides or other agents. However, the use of elevated temperature heating caps, for rather long periods of time, is required to obtain satisfactory results. Attempts have been made to apply these dyes with various types of anionic surfactants. Early attempts of combining a non-ionic direct dye with a shampoo led to unsatisfactory results due to failure to effectively clean the hair, failure to give satisfactory coloring results, or the need for excessively long hair contact times or high dye concentrations necessary at ambient temperatures. Excess dye led to better coloring effects, but most tended to be rinsed away, or the excess dye stained the skin.
Further, others have investigated the mechanism behind the diffusion of semi-permanent hair dyes, such as the nitrophenylenediamines into human hair fibers, as described in the Journal of The Society of Cosmetic Chemists, Vol. 36, pages 1-16 (January/February 1985), Diffusion Of Semi-permanent Dyestuffs Into Human Hair by S. K. Han, Y. K. Kamath and H. D. Weigmann. As described in this article, the diffusion of N.sub.1 -(2-hydroxyethyl)-2-nitro-p-phenylenediamine into human hair was investigated and it was concluded that the diffusion or deposition of the nitrophenylenediamine dye was dependent essentially only upon the pH and solvent composition of the dye bath and that the solvent effect was associated with the lower solubility of the nitrophenylenediamine dye in aqueous solution rather than in a 50 volume percent aqueous ethanol bath.
Others have attempted to determine the reasons for a low tinctorial power of other dyes, such as the henna color treatments in which 2-hydroxy-1,4-napthoquinone is the known active color principle, as disclosed in Commercial Premixed Henna Color Treatments and Conditioners, by Dolores Kenney, Cosmetics & Toiletries, Volume 95, June 1980, pages 43-52 and have found that in certain commercial henna-based dye compositions, the low tinctorial power of these commercial highlighting shampoos was attributable to the combination of anionic and amphoteric surfactants resulting in decreased tonal depth thus leading away from any such combination of anionic and amphoteric surfactants in a dye-shampoo composition.
As described in the article, Hair Colouring Shampoos, Soap, Perfume & Cosmetics, Vol. 48, June 1973, pages 357 and 358, betaine detergents have been used in hair coloring shampoos containing a basic dye or a quaternary dye. The betaines have been used with the basic and quaternary dyes since these dyes are incompatible with the most effective shampoo bases, such as the anionic lauryl sulfates. Accordingly, a non-ionic surfactant must be used with the basic and quaternary dyes to achieve compatibility even though such non-ionics are unsatisfactory as shampoo bases since they produce little lather in contact with soiled hair.
One recently published European application (published Apr. 17, 1985, Bulletin 85/16, Publication No. 137,178, Application No. 84109141.6) discloses a hair dye composition useful for increased deposition of nitrophenylene diamine dyes onto human hair, including a combination of surfactants and may include a long chain ether sulfate and a betaine, such as cocamidopropyl betaine. While this shampoo appears to be effective for increased deposition of nitrophenylenediamine dyes, the lathering and, therefore, cleansing properties are not as good as would be possible if the shampoo were based upon a non-ethoxylated long chain anionic, such as a lauryl sulfate. As well known, as presented by Roger Hart of W. R. Grace & Co. at Cosmo Expo 9, New York, June 24, 1981, FORMULATING IMPROVED LATHER, and in D & Cl, Feburary 1982, pages 34-36, the ethoxylated long chain anionic surfactants, such as the laureth sulfate salts, do not lather as well as the non-ethoxylated long chain anionic surfactants, such as sodium lauryl sulfate and, therefore, do not achieve consumer acceptance. As shown in FIG. 5 of the instant application, however, the combination of a non-ethoxylated long chain anionic sulfate, such as sodium lauryl sulfate, with a betaine, does not achieve increased deposition of nitrophenylene diamine dyes.
Quite surprisingly, in accordance with the present invention, it has been found that the combination of a long chain, non-ethoxylated anionic surfactant, having the formula CH.sub.2 -CH.sub.2n+1 OSO.sub.3 M wherein n=8 to 18 and M is any suitable cation, such as an alkali metal, ammonium, alkyloammonium, or amine together with one or more sultaine surfactants, substantially increases the deposition of nitrophenylene diamine dyes while achieving substantial lathering and, therefore, commercial acceptance.
In accordance with the present invention, new and unexpected lathering and shampooing results are achieved together with new, unexpected and even deposition of one or more nitrophenylenediamine dyes onto human hair at ambient temperature with relatively short contact times using a combination of a nonethoxylated long chain alkyl sulfate and a sultaine.